Automattic\WooCommerce\EmailEditor\Integrations\Utils

Html_Processing_Helper::normalize_rel_attribute │ private static │ WC 1.0

Normalize rel attribute by lowercasing, deduplicating tokens, and ensuring required tokens.

Method of the class: Html_Processing_Helper{}

No Hooks.

Returns

String. Normalized rel attribute value.

Usage

$result = Html_Processing_Helper::normalize_rel_attribute( ?string $rel_value, $require_security_tokens ): string;

?string $rel_value(required)

.

$require_security_tokens(true|false)

Whether to require noopener and noreferrer tokens.
Default: false

Html_Processing_Helper::normalize_rel_attribute() Html Processing Helper::normalize rel attribute code ^{WC 10.4.3}

private static function normalize_rel_attribute( ?string $rel_value, bool $require_security_tokens = false ): string {
	$allowed_tokens  = array( 'noopener', 'noreferrer', 'nofollow', 'external' );
	$required_tokens = $require_security_tokens ? array( 'noopener', 'noreferrer' ) : array();

	// If no rel value and no required tokens, return empty.
	if ( null === $rel_value && empty( $required_tokens ) ) {
		return '';
	}

	// Start with required tokens.
	$tokens = $required_tokens;

	// If rel value exists, parse and normalize it.
	if ( null !== $rel_value ) {
		$existing_tokens = preg_split( '/\s+/', trim( $rel_value ) );
		if ( false !== $existing_tokens ) {
			// Normalize existing tokens: lowercase, remove empty, filter allowed.
			$normalized_existing = array_filter(
				array_map( 'strtolower', $existing_tokens ),
				function ( $token ) use ( $allowed_tokens ) {
					return ! empty( $token ) && in_array( $token, $allowed_tokens, true );
				}
			);
			// Merge with required tokens, removing duplicates.
			$tokens = array_unique( array_merge( $tokens, $normalized_existing ) );
		}
	}

	// Return normalized rel attribute or empty string if no valid tokens.
	return empty( $tokens ) ? '' : implode( ' ', $tokens );
}